• Proceedings of the KIPE Conference
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• 2001.10a
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• pp.668-672
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• 2001

The utility interactive sinewave modulated inverter for the solar photovoltaic (PV) power conversion and conditioning with a new high frequency pulse modulated link is presented for domestic residential applications. As compared with the conventional full-bridge hard switching PWM inverter with a high frequency AC link, the simplest single-ended quasi-resonant soft switching sinewave modulated inverter with a duty cycle pulse control is implemented, resulting in size and weight reduction and low-cost. This paper presents a prototype circuit of the single-ended zero voltage soft switching sinewave inverter for solar power conditioner and its operating principle. In addition, this paper proposes a control system to deliver high quality output current. Major design of each component and the power loss analysis under actual power processing is also discussed from an experimental point of view. A newly developed interactive sinewave power processor which has $92.5\%$ efficiencty at 4kW output is demonstrated. It is designed 540mm-300mm-125mm in size, and 20kg in weight.

• The Korean Journal of Rehabilitation Nursing
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• v.6 no.2
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• pp.226-238
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• 2003

This study was started for the purpose of providing the basic data for continous managment of kidney transplantation patients after discharge. This study was conducted on 180 patients who received renal transplants at three hospital( B, M, P) pusan, korea. The data collection was done for june 1, to August 31, 2002. General characteristics, renal transplantaton characteristics, physical characteristics, the level of compliance and the degree of educational demand were done by the number and percentage, the mean, standard deviation. The level of compliance and educational demand followed by the characteristics of general and kidney transplantation were analyzed by t-test and ANOVA. The result were as fallows; 1. Man was higher than woman such as 60.0%, Mean age was 42.5 years old, Average total duration of after operation was 5.5 years. 2. Cases of systolic blood pressure over 140mmHg were 10.0%, cases of diastolic blood pressure over 90mmHg were 22.8% and obesity factor in BMI was 15.6%. The person who daily water intake amount is 5000cc was 0.6%, the case that daily urine output is below 1000cc was 8.9%, and the case that urine output is zero was 0.6%. 3. The mean score of compliance was 77.47 point, The score in medication part was highest such as 4.67 point, that in stress situation was lowest such as 3.50 point. 4. The average score of educational demand was 154.02 point, and physical state part was 4.36 points highest, activation part was 3.48 points lowest. As a role of nurse Confirmation of compliance is very important encourage to make good through regular hospital visitation, point out the noncompliance part and then increase compliance of renal transplantation patient As well there will be maintain the normal kidney function to satisfy educational demand through continous education.

• Proceedings of the IEEK Conference
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• 2003.07c
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• pp.2749-2752
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• 2003

Magnetocardiography is a very weak biomagnetic field generated from the heart. Since the magnitude of the biomagnetic field is in the order of a few pico Tesla, it is measured with a superconducting quantum interference device (SQUID). SQUID is a transducer converting magnetic flux to voltage, however, its range of linear conversion is very restricted. In order to overcome the narrow dynamic range. a flux locked loop is used to feedback the output field with opposite polarity to the input field so that the total Held becomes zero. This prevents the operating point of the SQUID from moving too far away from the null point thereby escape from the linear region. In this paper, an emulator for the SQUID sensor and feedback coil is proposed. Magnetic courting between the original field and the generated field by the feedback coil is emulated by electronic circuits. By using the emulator, FLL circuits are analyzed and optimized without SQUID sensors. The emulator may be used as a test signal for multi-channel gain calibration and system maintenance.

• Proceedings of the KIEE Conference
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• 2005.10b
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• pp.445-447
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• 2005

MCMA(modified constant modulus algorithm) accomplishes blind equalization and carrier phase recovery simultaneously. But, the error level of MCMA is not zero when the equalizer converges completely. Because the MCMA uses a special signal point instead of a original signal point. MCMA-DO(decision-directed) improves the steady-state performance but the performance of equalizer is decided by switching time between the MCMA and the DD. In this paper, according to the residual ISI(intersymbol interference) of the equalizer output, the most suitable switching time is decided automatically.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.66 no.9
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• pp.1325-1333
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• 2017

The sensorless control of blushless DC motor(BLDCM) is based on the $120^{\circ}$ control in which the back electromotive force(Back EMF) for estimating the position of the rotor can be detected. However, the $120^{\circ}$ control has a disadvantage that the torque constant is small as compared with $180^{\circ}$ control which can not detect the back EMF. The $150^{\circ}$ control which complements these problems makes it possible to detect the back EMF and improve the torque constant by 12.5% compared to the $120^{\circ}$ control. Therefore, this paper compares the output characteristics of BLDCM through finite element method analysis (FEA) by the conventional and proposed control methods of BLDCM for water circulation system and proposes design for downsizing and weight reduction of BLDCM according to secured torque constant. The validity of the proposed control and design proposal is proved through simulation and experimental results by comparing the output characteristics of $120^{\circ}$ control and $150^{\circ}$ control.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.10
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• pp.2197-2204
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• 2009

In this paper, we analyze the performance of the sphere decoding algorithm at MIMO system. The BER performance of this algorithm is the same as that of ML receiver, but computational complexity of SD algorithm is much less than that of ML receiver. The independent signals from each transmit antennas are modulated by using the QPSK and 16QAM modulation in the richly scattered Rayleigh flat-fading channel. The received signals from each receivers is independently detected by the receiver using Fincke & Pohst SD algorithm, and the BER output of the algorithm is compared with those of ZF, MMSE, SIC, and ML receivers. We also investigate the Viterbo & Boutros SD algorithm which is the modified SD algorithm, and the BER performance and the floting point operations of the algorithms are comparatively studied.

• The Transactions of the Korean Institute of Power Electronics
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• v.5 no.5
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• pp.508-514
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• 2000

A single-stage power factor correction AC/DC converter with a simple link voltage suppressing circuit (LVSC) for the universal line application is proposed. Using this simple circuit, a low link voltage can be realized without deadbands at line zero-crossings. The proposed converter is analyzed and a prototype converter with 5V, 12A output is implemented to verify the performance. The experimental results show that the link voltage stress and efficiency are about 447V and 81%, respectively.

• Journal of Power Electronics
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• v.4 no.3
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• pp.138-151
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• 2004

In this paper, a constant frequency phase shifting PWM-controlled voltage source full bridge-type series load resonant high-frequency inverter using the $4^{th}$ generation IGBT power modules is presented for innovative consumer electromagnetic induction heating applications, such as a hot water producer, steamer and super heated steamer. The bridge arm side link passive capacitive snubbers in parallel with each power semiconductor device and AC load side linked active edge inductive snubber-assisted series load resonant tank soft switching inverter with a constant frequency phase shifted PWM control scheme is evaluated and discussed on the basis of the simulation and experimental results. It is proved from a practical point of view that the series load resonant and edge resonant hybrid high-frequency inverter topology, what is called, DE class type, including the variable-power variable-frequency regulation function can expand zero voltage soft switching commutation area even under low output power setting ranges, which is more suitable and acceptable for newly developed induction heated dual pack fluid heaters. Furthermore, even the lower output power regulation mode of this high-frequency load resonant tank inverter circuit is verified so that this inverter can achieve ZVS with the aid of the single auxiliary inductor snubber.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.1066-1071
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• 2005

This paper presents the two lossless auxiliary inductors-assisted voltage source type half bridge (single ended push pull: SEPP) series resonant high frequency inverter for induction heated fixing roller in copy and printing machines. The simple high-frequency inverter treated here can completely achieve stable zero current soft switching (ZCS) commutation for wide its output power regulation ranges and load variations under its constant high frequency pulse density modulation (PDM) scheme. Its transient and steady state operating principle is originally described and discussed for a constant high-frequency PDM control strategy under a stable ZCS operation commutation, together with its output effective power regulation characteristics-based on the high frequency PDM strategy. The experimental operating performances of this voltage source SEPP ZCS-PDM series resonant high frequency inverter using IGBTs are illustrated as compared with computer simulation results and experimental ones. Its power losses analysis and actual efficiency are evaluated and discussed on the basis of simulation and experimental results. The feasible effectiveness of this high frequency inverter appliance implemented here is proved from the practical point of view.

• Proceedings of the KIPE Conference
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• 2005.07a
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• pp.774-777
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• 2005

In this paper, a constant frequency phase shifting PWM controlled voltage source full bridge-type series load resonant high-frequency inverter using the IGBT power modules is presented for innovative consumer electromagnetic induction heating applications such as a hot water producer, steamer and super heated steamer. The full bridge arm side link passive quasi-resonant capacitor snubbers in parallel with the each power semiconductor device and high frequency AC load side linked active edge inductive snubber-assisted series load resonant tank soft switching inverter with a constant frequency phase shifted PWM control scheme is discussed and evaluated on the basis of the simulation and experimental results. It is proved from a practical point of view that the series load resonant and edge resonant hybrid high-frequency soft switching PWM inverter topology, what is called class DE type. including the variable-power variable-frequency(VPVF) regulation function can expand zero voltage soft switching commutation range even under low output power setting ranges, which is more suitable and acceptable for induction heated dual packs fluid heater developed newly for consumer power utilizations. Furthermore, even in the lower output power regulation mode of this high-frequency load resonant tank high frequency inverter circuit it is verified that this inverter can achieve ZVS with the aid of the single auxiliary inductor snubber.